DHT22 Temperature & Humidity Sensor

⚡Quick Facts

• Measures Air temperature and humidity
• Pins 3 wires — power, ground, data
• Best for Weather stations and room monitors
• Update speed New reading every 2 seconds

📋Technical Specifications

Arduino library: DHT sensor library by Adafruit

• Temperature range: −40°C to 80°C
• Humidity range: 0–100% RH
• Operating voltage: 3.3 V (recommended for ESP32)
• Single data pin with digital protocol
• Sampling rate: 0.5 Hz (every 2 seconds)

📍Pinout

• 1 · VCC Power ESP32 3.3 V Use 3.3 V for direct ESP32 wiring
• 2 · DATA Signal ESP32 GPIO4 Add 10 kΩ pull-up to 3.3 V on bare sensors; many modules include one
• 3 · GND Ground ESP32 GND Common ground with the ESP32

🔗Wiring

A DHT22 module with three pins is the easiest way to start. Match each pin to the ESP32 as shown below.

1. 1

   Unplug USB. Place the DHT22 module on your breadboard.

2. 2

   Connect VCC on the module to 3.3 V on the ESP32.

3. 3

   Connect GND on the module to GND on the ESP32.

4. 4

   Connect DATA on the module to GPIO4 on the ESP32.

5. 5

   Double-check — VCC to 3.3 V, GND to GND, DATA to GPIO4.

6. 6

   Plug in USB. Your code must use the same GPIO number.

⌨️Code Example

Copy into Arduino IDE. Install the library listed above first.

#include "DHT.h"

#define DHTPIN 4
#define DHTTYPE DHT22

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(115200);
  dht.begin();
}

void loop() {
  float temp = dht.readTemperature();
  float humidity = dht.readHumidity();

  if (isnan(temp) || isnan(humidity)) {
    Serial.println("Read failed — check wiring");
  } else {
    Serial.printf("Temp: %.1f C  Humidity: %.0f%%\n", temp, humidity);
  }

  delay(2000);
}